A mixed analytical-numerical method for the acoustic radiation of a double elastic spherical shell in finite-depth water

Abstract

A mixed analytical-numerical method is proposed to evaluate the acoustic radiation of a double elastic spherical shell in finite-depth water by combining the analytical method with the numerical Wave Based Method (WBM) [or Wave Superposition Method, WSM]. The effects of reflection from both the free surface and the seabed are considered. The correctness of this method is verified through several numerical examples. Theoretically, this method can be extended to address the acoustic radiation problem of a double spherical shell in more complex hydroacoustic waveguide environment, because only a change of Green's function used in the WBM is needed. The method presented in this work can provide a benchmark, which is quite scarce at present, for the fluid-structure coupled vibration, acoustic radiation and sound propagation of three-dimensional bodies of an arbitrary shape in the hydroacoustic waveguide environment. Furthermore, the influence of free surface and seabed boundaries on the behaviors of structural vibration, acoustic radiation and sound propagation is presented. Some physical images are also included to illustrate the mechanism more clearly.